The peppered moth are a species of night-flying moth that have been studied extensively for over 200 years by biologists. They are known to be prime examples of the power of natural selection.
In England, there are two variants of this moth: one that has a peppery white appearance and another that is much darker, almost black. Originally, the white variant was much more common, as they could easily camouflage themselves on trees covered in light-coloured lichen.
However, during the Industrial Revolution, the heavy pollution killed the sensitive lichen causing trees to expose their dark bark. This caused the white moth to be extremely visible, making them easy prey for birds and other predators. The change in environment resulted in black moths, that used to be disadvantaged, to have a better chance of survival, causing the black moth population to become superior.
As people became more aware of air pollution and England began cleaning up its environment, lichen returned to the tree and the table turned once more – the dark moths were now better targets and were heavily preyed on. Instead, the white moth retook the majority position, thus showing how the environment affects which traits survive in a population.